Control means for buttonholing apparatus



July 14, 1953 W. T. LEONAR D CONTROL MEANS FOR BUTTONHOLING APPARATUS 2Sheets-Sheet 1 Filed Nov. 3, 1951 M'lliam 2 11; $55 2 QM A'ITORNEY July14, 1953 w. 'r. LEONARD CONTROL MEANS FOR BUTTONHOLING APPARATUS 2Sheets-Sheet 2 Filed NOV. 3, 1951 ATToR'N Y Patented July 14, 1953CONTROL MEANS FOR BUTTONHOLING APPARATUS William '1. Leonard, Rcadingla., assignor to Textile Trimming & Boarding Machine 00., Inc., Reading,Pa.,' a corporation of Pennsyl- Vania Application November 3, 1951,Serial No. 254,745

6 Claims; Cl. 112- 68) 1 The present invention relates to control meansfor buttonholing apparatus, such, for example, as a buttonhole stitchingand cutting machine, and, more particularly, to a strand or threadcontinuity operated arrangement for controlling the cuttinginstrumentality of buttonholing apparatus.

Machines for automatically stitching button holes are available whichperform a complete stitching operation following which the button holeis out. When the thread in the machine breaks, a special repair job onthe workpiece is necessary due to the fact that the buttonhole is outbefore it is fully or properly stitched. The present invention providesa strand or thread continunity operated device which prevents thebuttonhole cutting operation if the thread breaks or otherwise losesproper operating tension. Solely by way of example, the threadcontinuity operated arrangement of the present invention is shown in thesetting of a buttonhole sewing machine of a well known type. selectedfor illustrative purposes is the Singer sewing machine No. 71-101manufactured by'the Singer Manufacturing Company. A similar machine isthe Singer sewing machine No. 71-107.

Parts of these machines which are to be controlled in accordance withthe present invention are de provision of a unitary control device ofnovel form which can be installed in an existing ma chine without, orsubstantially without, modification thereof.. The invention also residesin the novel cooperation of the device provided by this invention withthe mechanism with which it is associated.

The primary object of the present invention is to provide a novel strandor thread cantinuity operated arrangement for controlling operation of asewing machine.

Another and related object of the invention is to provide novel meansfor preventing the cutting of a buttonhole in the process of beingfinished upon breakage of the buttonhole stitching thread. i 1

In the disclosure of The machine 7 2 A'further object of the inventionis to provide a unitary device which can be readily installed in anexisting buttonhole machine whereby to prevent operation of a part orparts of the existing machine in the event of thread breakage. Otherobjects and advantages of the invention will, of course, become apparentand immediately suggest themselves to those skilled in the art to whichthe, invention is directed from a reading of the following specificationin connection with the accompanying drawing in which: A

Fig. l is a fragmentary perspective view of a buttonhole stitching andcutting machine including a deviceconstructed in accordance with thepresent invention;

Fig. 2 is a fragmentary 'view in plan of the machine of Fig. 1 includingonly parts thereof which are referred to in describing the functioningof the present invention;

Fig. 3 is a fragmentary view inside elevation of the parts of Fig. 2and;

Fig. 4 is a view in perspective of the device of. I this invention whichis to be installed in an.

existing machine.

Referring to the drawing, and for the-present to Fig. l thereof, thereis shown a portion of a machine H) for making buttonholes in a workpiece such as a shirt. The machine I0 is of standard make, as statedabove, and therefore only. the parts of the machine actuated or.controlled in accordance with the present invention will be described indetail. The forwardly extending arm l2 of the machine is provided with ahead I 4 which houses the needle bar 16 and its driving mechanism (notshown). The top rear, portion l8 of the arm [4 houses the needlevibrating mechanism and part of a stitch control mechanism not essentialto an understand ing of the present invention for controlling certainsteps in the stitching process known as barring whereby the ends of thebuttonhole are finished with a bar stitch. I

The course of the stitching thread i9 is shown in Fig.1 1 of thedrawing. The thread is stored in an unwinder rack (not shown) or anyconvenient reel and it passes downwardly'through a hole 2| in the top ofa thread leader post 22. The thread emerges through a hole 24 and passesto a tension device 26 provided with the usual discs. The tension device26 is controlled by a rod 28, the purpose of which is not directlyconcerned with the present invention. From the tension device, thethread goes to a thread guide3l and from there to a tensioning device33. From the tensioning device 33, the thread I9 goes to a spring takeup34. A tension thread guide 36 guides the thread (in the absence of thedevice 38 of the present invention) through a hole in the end of athread take-up lever 4| and from there into a slot 43 in the face plateof the head I4. From the slot, the thread goes into the eye of theneedle 46.

With the device 38 of this invention installed in the machine I0, thethread I9 is led from the thread guide 36 under a hook 5| at the end ofthe downwardly extending rod 53 of the device 38. The functioning of thedevice 38 will be described more in detail hereinafter. From thepreceding descri tion it will be seen that when the tension of thethread is maintained, the rod 53 will be biased upwardly as viewed onFig. 1 of the drawmg.

The needle 48 cooperates with a work piece which is moved by a workpiece clamping device 56. The latter executes a path which is suitablefor stitching the sides and ends of a buttonhole. Since the specificform of work piece clamping device and its function is not directly apart of the present invention, its functioning and control will not befurther described.

Cutting of the buttonhole is accomplished by a knife 58 clamped in aknife holder 59. The latter is mounted at the end of a knife bar 63. Adownward thrust, for cutting purposes, is imparted to the bares by aknife bar driving lever 65 which is pivoted on a knife bar driving leverhinge screw 68 which is. received in a tapped hole in the arm I2. Aknife bar connecting link (not shown) couples the lever 66 to the bar63. A knife bar driving lever spring H anchored by a knife bar drivingspring screw I3, biases the lever 66 and the bar 63 upwardly.

A driving stroke for the knife bar driving lever is imparted by anintermediate knife bar driving lever I6 through an intermediate knifebar driving lever connecting link I8. The latter is provided with a slot8I which receives a screw stud 83 secured to the lever 66. Pivotalconnection for the link I8 is provided by a hinge screw 84. The slot BIand the screw 83 in conjunction with a knife bar disengaging lever 86provides a controlled lost motion connection. The lever 86 is pivoted,to the link. 18 b means of a hinge screw 88. The lever 76 is pivoted tothe machine body (fragmentarily shown) by means of a cap screw.

80. An intermediate knife bar driving lever roller 92, secured to a partof the stop mechanism (not shown), operates the knife driving leversystem described above.

The knife bar disengaging lever 86 is provided with a shoulder 94 whichcan engage the screwv stud 83 to cause the lever 50 to be rocked whenthe right hand end of the lever '16 rises. This drives the knife 53downwardly to cut the buttonhole. An arm 55 extending from the knife bardisengaging lever S6 rests on a tongue 96 which extends upwardly from aknife bar disengaging lever catch !0 I. The catch IOI is pivotallymounted at the endof a fixed bracket I93 by means of a hinge screw I06and a nut I118. The catch IUI, as shown in Fig. 2, is angularly shaped,being composed of two arms III and IIZ. The arm III, as described above,is pivoted on the bracket I03 by means of the hinge screw I05.

The arm I I 2 is provided with a roller [I4 which is periodicallyengaged by a disengaging lever catch tripping point H6. The latter iscarried by a collar H8 mounted on. a shaft I2I which is driven by a feeddriving gear I24. The gear I24 meshes with a gear I25 connected to thecycling mechanism of the machine I0. A spring I26 anchored to thebracket I03 serves to bias the knife bar disengaging lever to the leftas viewed in Fig. 1. A spring I28 biases the knife bar disengaging levercatch in a clockwise direction as viewed in Fig. 2. A stop I23 for thecatch IN is schematically shown.

The parts thus far described are part of the sewing machine for sewingand cutting buttonholes. As pointed out above, the showing of theseparts is modified for the sake of convenience of illustration. Theunitary control device 33 of novel form, which can be installed in themachine so far described by way of a setting for the present invention,will now be described together with the manner of its functioning incooperation with the sewing machine parts. Fig. 4 of the drawing will bereferred to for the present in describing the device 38. A plate memberI is notched as indicated at I43 so that it will fit around thesupporting pin for the tension device 26 previously described or anyother convenient part of a sewing machine. A hole I46 receives a screwI41 of the machine I0 which supports a thread guide. A downwardlyextending bracket I 49 provides pivotal support for a pair of arms I5Iand I52. These arms are rigidly connected and are pivoted to the bracketI49 by means of a pintle or hinge screw I54. The arm I5I carries thepreviously described rod 53 which is provided with the hook 5I.

The arm I52 has an arm I56 pivoted thereon by means of a hinge screwI58. The arm I 56 has laterally extending tongue I59 and a tongue IN.The unitarily joined arms I5I and I52 have a rod 104 connected theretoupon which a counterweight IBS is adiustably slidable. A set screw I63can be used to fix the position of the counterweight I66.

In operation of the machine I0 with the device 38 installed therein, solong as the thread I! is intact, the arm I5I is raised and the tongueI59 does not interfere with operation of the knife bar disengaging lever86. With the thread unbroken, when the point I I5 trips the knife bardisengaging lever catch IOI, the tongue 98 is withdrawn which permitsthe shoulder 94 on the lever 86 to engage the screw stud 83 and effect abuttonhole cutting operation.

When the thread I9 breaks, the arm I5I drops by gravity and thelaterally extending tongue I59 moves to the left as viewed in Fig. l tolie over the hinge screw I06. When the disengaging lever catch trippingpoint H5 moves the catch IOI to shift the tongue 99, the knife bardisengaging lever 86 is prevented from moving under the influence of thespring I26 by engagement of an inturned extension HI with the laterallyextending tongue I59 which rests on the hinge screw I06 at this time.The shoulder 84 cannot engage the screw stud 83 so that the lever 66 isnot moved to drive the knife bar 63.

The invention claimed is:

l. A device for application to a buttonhole sewing machine having aworkpiece cutter to prevent operation of the cutter in the event ofsewing thread failure, said device comprising a bracket, means on saidbracket to facilitate connection thereof to an existing stationary partof the sewing machine, a pair of rigidly joined arms pivoted to saidbracket, said arms being angularly disposed with respect to each other,the first of said arms having a rod secured thereon to extend from saidfirst arm substmtially at a right angle, a hook at the end of said rodfor engagement with a tensioned sewing thread whereby to be supported bysaid thread, a member pivoted to the second of said arms adjacent itsfree end, said member having an extension substantially aligned with thebody of said member, and a tongue extending laterally from said member.

2. A device for application to a buttonhole sewing machine having aworkpiece cutter to prevent operation of the cutter in the event ofsewing thread failure, said device comprising a bracket, means on saidbracket to facilitate connection thereof to an existing stationary partof the sewing. machine, a pair of rigidly joined arms pivoted to saidbracket, said arms being angularly disposed with respect to each other,adjustable biasing means associated with said arms, the first of saidarms having a rod secured thereon to extend from said first armsubstantially at a right angle, a hook at the end of said rod forengagement with a tensioned sewing thread whereby to b supported by saidthread, a member pivoted to the second of said arms adjacent its freeend, said member having an extension substantially aligned with the bodyof said member, and a tongue extending laterally from said member.

3. A device for application to a buttonhole sewing machine having aworkpiece cutter to prevent operation of the cutter in the event ofsewing thread failure, said device comprising a bracket, means on saidbracket to facilitate connection thereof to an existing stationary partof the sewing machine, a pair of rigidly joined arms pivoted to saidbracket, said arms being angularly disposed with respect to each other,an adjustable counter weight secured to said arms, the first of saidarms having a rod secured thereon to extend from said first armsubstantially at a right angle, a hook at the end of said rod forengagement with a tensioned sewing thread whereby to be supported bysaid thread, a member pivoted to the second of said arms adjacent itsfree end, said member having an extension substantially aligned '"withthe body of said member, and a tongue extending laterally from saidmember.

4. In a buttonhole sewing machine having means to perform a cuttingoperation on a workpiece, a knife, a first lever for driving said knife,a second lever, means to impart a driving stroke to said second lever, alink pivoted to said second lever, a lost motion connection between saidlink and said first lever, a member pivoted to said link for lockingsaid lost motion connecton, biasing means for said member, a trip forsaid memher, a pivotal support for said trip, a tongue on said member,and movable means controlled by thread tension for engagement betweensaid tongue and said pivotal sup-port, means whereby said movable meansis prevented from engaging said pivotal support by tension existing in asewing thread, said movable means having means associated therewith tobias it for engagement with said pivotal support upon thread failure.

5. In a buttonhole sewing machine having means to perform a cuttingoperation on a workpiece, a knife, a first lever for driving said knife,a second lever, means to impart a driving stroke to said second lever, alink pivoted to said second lever, a slot in said link, a projectionfrom said first lever movable in said slot to. provide a lost motionconnection between said link and said first lever, a member pivoted tosaid link for locking said lost motion connection, a trip for saidmember, a pivotal support for said trip, a tongue on said member, andmovable means controlled by thread tension for engagement between saidtongue and said pivotal support, means whereby said movable means isprevented from engaging said pivotal support by tension existing in asewing thread, said movable means having means associated therewith tobias it for engagement with said pivotal support upon thread failure.

6. In a buttonhole sewing machine having means to perform a cuttingoperation on a workpiece, a knife, a first lever for driving saiu knife,a second lever, means to impart a driving stroke to said second lever, alink pivoted to said second lever, a lost motion connection between saidlink and said first lever, a member pivoted to said link for lockingsaid lost motion connection, a trip for said member, a pivotal supportfor said trip, a tongue on said member, a second member controlled bythread tension and being movable for engagement between said tongue andsaid pivotal support, means whereby said second member is prevented fromengaging said pivotal support by tension existing in a sewing thread,said second member having means associated therewith to bias it forengagement with said pivotal support upon thread failure.

WILLIAM T. LEONARD.

References Cited in the file of this patent IbbOtt Oct. 24, 1944

